Food processing isn’t always a bad thing: Cooking and preparing raw ingredients at home is also processing them. But the word “processed” is almost always reserved for commercial foods, usually packaged. Highly processed foods are industrially formulated mixtures that are no longer recognizable as their original plant or animal sources—everything from hot dogs and margarine to ice cream, candy, and many packaged snack foods. Such foods, which supply more than half the daily calories in most U.S. households, lack key nutrients and fiber and are high in sugars and sodium.
Stephen Colbert may be on to something. UCLA Center for Human Nutrition researchers divided study participants into two groups, each of which were fed a nearly identical low-cal diet for 12-weeks. The only difference between the groups was what they were given to eat as an afternoon snack. One group ate 220-calories of pretzels while the other group munched on 240-calories worth of pistachios. Just four weeks into the study, the pistachio group had reduced their BMI by a point, while the pretzel-eating group stayed the same, and their cholesterol and triglyceride levels showed improvements as well.
Kimchi is a spicy Korean condiment that's made with fermented cabbage and is a great source of vitamins A, B, and C. Because it's fermented (like sauerkraut), kimchi contains tons of those good probiotics that aid the body in digestion. A recent study in the Proceedings of the National Academy of Science found that maintaining healthy bacteria in your gut can improve gut lining, which in turn could help reduce fat mass and inflammation.
Diets to promote weight loss are divided into four categories: low-fat, low-carbohydrate, low-calorie, and very low calorie.[27] A meta-analysis of six randomized controlled trials found no difference between the main diet types (low calorie, low carbohydrate, and low fat), with a 2–4 kilogram weight loss in all studies.[27] At two years, all of the diets in the studies that reduced calories caused equal weight loss regardless of whether changes in fat or carbohydrate consumption were emphasized.[28]
Avocados are rich in monounsaturated fatty acids, dietary fiber, potassium and phytochemicals. People who eat avocados tend to have lower BMI, body weight and waist circumference than people who skip this green superfood, per a study in Nutrition Journal. While avocados are higher in calories than other fruits and vegetables, their satisfying fat and fiber combo may help you slim down. Add some to your salad, sandwich or taco night for a burst of creaminess and flavor.
In general, healthy eating ingredients are found around the outer edges of most grocery stores, while the center aisles are filled with processed and packaged foods that aren’t good for you. Shop the perimeter of the store for most of your groceries (fresh fruits and vegetables, fish and poultry, whole grain breads and dairy products), add a few things from the freezer section (frozen fruits and vegetables), and visit the aisles for spices, oils, and whole grains (like rolled oats, brown rice, whole wheat pasta).

At least half your grains should be whole grains, such as whole wheat, oats, barley, or brown rice. Whole grains retain the bran and germ and thus all (or nearly all) of the nutrients and fiber of the grain. One sure way of finding whole grains is to look for a product labeled “100% whole wheat” or “100%" of some other whole grain. You can also look for a whole grain listed as the first ingredient, though there still may be lots of refined wheat in the product. Another option is to look for the voluntary “Whole Grain Stamp” from the Whole Grains Council. Or try this tip: Look for less than a 10-to-1 ratio of “total carbohydrates” to “fiber” on the nutrition label.

Losing weight isn't all about exercise – what you eat matters too. But nobody wants to eat diet food that makes them feel like they're going to gnaw their arm off before dinner. That's why registered dietitians say it's important to up your intake of veggies, grains, nuts, and other foods that are full of fiber, protein, and other pound-dropping nutrients. These options will help you prevent cravings and keep you full straight through your usual afternoon snack.